Ophthalmic lens here means any optical component made from mineral and/or organic material, at least partially transparent and suitable for being placed before a wearer's eye, regardless of the optical function of said component. It may in particular have an antiglare protective function by absorption of part of the light, called antisolar function, a contrast reinforcing function by coloration or by polarization filtering, an ametropia correcting function, etc. It may in particular be an afocal, unifocal, bifocal, multifocal or progressive lens.
Ametropia correcting lenses are conventionally produced by forming a transparent material with a refractive index higher than air. The shape of the lenses is selected so that the refraction at the interfaces between the material and the air causes appropriate focusing of the light on the wearer's retina. The lens is generally cut out to be fit into a frame, with an appropriate positioning with regard to the pupil of the corrected eye.
In certain distribution circuits, blanks of corrective lenses that are manufactured industrially are finished to adapt them to the ametropia of an eye to be corrected. The finish consists for example in machining and polishing the back of the blank. This method combines the industrial production of the blanks, thereby reducing their cost, and the need to personalize the correction. However, the reshaping of lenses according to the wear's needs requires specialized tools and skills. These must be available close to the place of distribution to satisfy the current desire for rapid delivery of the lenses. This creates a strong need for investment and organization.
In the case of optical functions other than ametropia correction, the personalization possibilities are highly restricted. The wearer is generally offered a choice among a small number of lens colors, degrees of light absorption, sometimes polarizations, which correspond to lens models or blanks available ex-works. It is conceivable to increase the number of possibilities offered, but this would be to the detriment of the unit production cost. The possibilities of varying an absorption or coloration parameter along the lens surface are even more limited, and in any case are not appropriate to the individual needs or desiderata of the wearers.